So lets say you have database type data in an XML string called $xmlstring with the key or item ID as an XML Attribute and all content data as regular XML Elements, as above. SimpleXML processes the Attributes as an array, so we can play along and push the Attributes into an array. Then we can get the value of any specific Attribute we want by addressing it by name, such as "ID".

Just passing by 'xml' as namespace argument of the attribute() method didn't work out for me. Passing by the complete namespace URI works also if it is not explicitly defined in the underlying XML document.

Also, $simpleXmlElement->getNamespaces() does not return anything of use.